diff options
| -rw-r--r-- | lib/Target/README.txt | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/lib/Target/README.txt b/lib/Target/README.txt index 17617ad..e59c286 100644 --- a/lib/Target/README.txt +++ b/lib/Target/README.txt @@ -73,7 +73,25 @@ This has a number of uses: //===---------------------------------------------------------------------===// -Make the PPC branch selector target independant +We should recognized various "overflow detection" idioms and translate them into +llvm.uadd.with.overflow and similar intrinsics. For example, we compile this: + +size_t add(size_t a,size_t b) { + if (a+b<a) + exit(0); + return a+b; +} + +into: + + addq %rdi, %rbx + cmpq %rdi, %rbx + jae LBB0_2 + +when it would be better to generate: + + addq %rdi, %rbx + jno LBB0_2 //===---------------------------------------------------------------------===// |